热处理制度对TB2钛合金焊接接头性能的影响

研究了TB2高强钛合金冷轧板材分别经真空电子束焊和氩弧焊接, 并在β单相区和α β两相区温度固溶 时效处理后, 其力学性能和显微组织的变化.结果表明: TB2钛合金具有良好的可焊性, 任何焊接方法不同热处理下的接头强度系数均大于0.9, 塑性均低于母材, 其中710 ℃/30 mim AC 520 ℃/8 h处理的试样, 综合力学性能较高, 焊缝区内有弥散α析出的β晶粒, 而且焊缝熔合线附近是整个焊缝的最薄弱部位;比较不同焊接方法, 氩弧焊的接头强度较好, 但塑性很差, 热影响区较宽, 晶粒长大明显.该试验结果为组焊成型TB2压力容器提供了参考.     

车用TC15钛合金激光焊接接头显微组织及力学性能研究

通过拉伸试验、硬度测试及金相分析等方法,对TC15钛合金激光焊接接头的显微组织和力学性能进行研究。结果表明,焊缝的深宽比在4~6之间波动,焊缝区域的晶粒形貌为柱状结构,且从焊缝中心线往外呈对称分布状态,主要为β相大晶粒。热影响区组织由细晶区、粗晶区及再结晶区构成,熔合线附近区域的晶粒明显粗化。焊缝区具有相对稳定的硬度值分布,硬度与热影响区的粗晶区相近。较低焊接电流焊缝试样具有最低的抗拉强度,其断裂部位为焊缝区;随着焊接电流的增大,焊接接头抗拉强度得到提高。     

国产A6N01铝合金型材MIG焊接头的微观组织与力学性能

利用金相观察、显微硬度测定、拉伸和弯曲性能测试等方法研究了A6N01-T5铝合金型材MIG焊接接头的显微组织和力学性能.结果表明：焊接接头焊缝中心金属为明显的激冷形成的铸态组织,呈等轴晶状;熔合区靠近焊缝侧的结晶形态为沿散热方向排列的柱状晶,邻近熔合区的热影响区晶粒粗化.焊缝中心处具有较高的显微硬度,在距离焊缝中心10~12 mm处的热影响区显微硬度值最低.国产A6N01-T5铝合金型材焊接接头抗拉强度达到欧洲标准DIN EN 288-4的要求.     

TA19钛合金电子束焊接头微观组织与性能研究

采用电子束焊接方法对TA19钛合金进行焊接,分析了电子束焊接头各区域的显微组织类型及形貌,测试了接头的显微硬度、室温拉伸、疲劳裂纹扩展速率及断裂韧性等力学性能,并与TA19钛合金母材进行对比。研究表明,焊缝区为粗大的柱状晶组织并存在大量相互交错分布的针状马氏体相,热影响区内随着离熔合线距离的增加马氏体数量逐渐减少;焊缝区显微硬度最高,比母材区显微硬度高出约HV80,随着向母材区过渡显微硬度逐渐降低;焊接接头室温抗拉强度、屈服强度性能及断面收缩率均与母材基本相当,但延伸率略有下降;焊缝区粗大的柱状晶组织硬度高,脆性大,导致焊缝区对疲劳裂纹扩展的抗裂性要低于母材;母材及焊缝KIC值分别为54.49和52.88 MPa·m^1/2,母材抵抗裂纹扩展断裂的能力略好于焊缝。     

Al-12.7Si-0.7Mg合金焊接热裂纹倾向性研究

在不填丝的情况下,采用自动TIG焊对Al-12.7Si-0.7Mg合金热挤压型材进行鱼骨状裂纹试验.通过目测、金相观察、EDS分析、显微硬度测定等方法研究了该合金的焊接热裂纹倾向性及焊接接头显微组织与硬度分布.结果表明:焊缝表面与内部均未发现裂纹,合金焊接热裂纹倾向性低.焊缝区是母材在焊接热作用下熔化后激冷形成的铸态组织,主要由α-Al、Al-Si共晶相以及少量Mg2Si、含Fe相等金属间化合物构成。经T6处理后,焊缝区中呈密集纤维状的共晶硅粒状化.显微硬度测试结果显示焊态接头焊缝区硬度最高,熔合区急剧下降,在热影响区达到最低,经T6处理后,接头各区显微硬度整体提升,且波动较小.     

TC4钛合金真空电子束焊焊接接头组织性能与腐蚀行为研究

真空电子束焊具有能量集中度高、热影响区小等优点,在钛合金焊接领域被广泛应用。本文研究了TC4钛合金薄板真空电子束焊对接组织性能以及在不同腐蚀介质中的腐蚀行为及特征。研究结果表明:接头母材区组织是等轴α相和间隙β相的机械混合,焊缝区组织为针状马氏体(α'相),热影响区由原始α相、β相加α'相构成;接头显微硬度明显高于母材且随着与母材距离的增加,硬度逐渐增加;同时焊缝区网篮组织的形成使接头拉伸强度和断面收缩率更高,塑性更好。在3.5%NaCl溶液中,母材的腐蚀倾向大于焊缝,而在10%HCl溶液中则相反,焊缝成为薄弱环节;同时,焊接接头在10%HCl溶液中自腐蚀电流显著高于在3.5%NaCl溶液中,说明介质对接头的电化学腐蚀性能影响显著。     

X100级管线钢CO_2气体保护焊接试验研究

通过拉伸、冲击、硬度、焊后热处理等试验方法,研究了不同焊接热输入量对CO_2气体保护焊接条件下X100级管线钢焊接接头力学性能和显微组织的影响。结果表明:随着焊接热输入量增加,显微组织逐渐粗化;当焊接热输入量为1.91 kJ/mm时,焊缝中粒状贝氏体数量增多,针状铁素体数量减少,晶粒和M-A组元尺寸明显粗化,焊接接头的强韧性、硬度均下降;当焊接热输入量为1.17 kJ/mm时,其焊接接头能获得最佳的力学性能和显微组织。经过焊后热处理,距离焊缝2~4 mm处HAZ的HV10硬度为230~240,下降明显,焊缝硬度波动变小,距离焊缝4~6 mm处的HAZ和母材硬度变化不大。     

喷射成形7055铝合金激光焊接头组织性能研究

采用激光焊接方法对2 mm厚喷射成形的7055铝合金进行了焊接实验。通过背散射电子衍射技术(EBSD)、扫描电镜(SEM)、能谱仪(EDS)、透射电镜(TEM)、显微硬度和室温拉伸试验等测试方法对焊接接头的微观组织和力学性能进行了分析。结果表明:7055铝合金激光焊接头热影响区无明显的软化,焊缝显微硬度最低,约为母材的77%,接头的抗拉强度和伸长率分别约为母材的61%和4.1%。热影响区观察到发生了再结晶的等轴晶粒,但晶内可观察到弥散的η'相;熔合线附近形成了晶粒取向随机分布的细小的等轴非枝晶区;焊缝区靠近熔合线为柱状枝晶,靠近焊缝中心为胞状枝晶,晶内无弥散强化相。综上所述,这些区域的微观组织特征揭示了焊接接头的不均匀性,其综合机械性能较母材有所下降,焊缝成为接头的最薄弱环节。     

焊接方法对钛合金板焊接接头组织性能的影响研究

本文通过对不同焊接方法下钛合金板接头组织性能展开研究，对比分析了氩弧焊、冷焊、激光焊、电子束焊以及电阻点焊之间的异同之处，对使用各焊接方法的焊接接头进行强度、硬度、塑性、韧性对比，综合判断各焊接方法的优缺点与适用环境。实验结果表明：氩弧焊最好使用TA18焊丝，接头强度平均值为982.5MPa，伸长率为7.5%，强度和塑性匹配良好；冷焊焊缝区硬度小于热影响区，且不宜发生变形，平均接头强度为974.5MPa；激光焊接头伸长率与母材相似，平均接头强度为956.5MPa；电阻点焊接头的剪切应力与薄板件厚度、焊接电流强度和通电时间等因素正向相关。综合分析发现，对焊接质量要求较高的，需要使用高精度的电子束焊接。     

纯镍N6填丝等离子焊接工艺及接头组织性能的研究

试验采用等离子弧焊设备对工业纯镍N6板材进行填充焊丝等离子焊接工艺试验。借助光学显微镜(OM)、扫描电镜(SEM)、能谱分析(EDS)、X射线衍射仪(XRD)和显微硬度计等手段分析了焊接接头的微观组织和力学性能。结果表明:采用合理的焊接工艺参数可以得到成形良好的焊缝,填丝焊接接头抗拉强度为333 MPa,其抗拉强度达到母材强度的97.6%,不填丝焊接接头抗拉强度为240 MPa,达到母材强度的70.5%;母材为均匀细小的等轴晶,填丝接头焊缝处呈树枝状结晶且晶粒粗大,热影响区靠近熔池部分的晶粒过热长大,靠近母材部分为均匀细小的等轴晶;填丝接头基体为γ-Ni组织,同时存在γ'(Ni3(Al,Ti)C)强化相,填丝接头拉伸断口表现为韧-脆混合断裂,焊接接头硬度最低值出现在热影响区;与母材相比,不填丝接头焊缝区与热影响区晶粒粗大,其基体组织为单相奥氏体,不填丝接头拉伸断口表现为脆性断裂,硬度最低值出现在接头热影响区。     

China's Major Non-ferrous Metals Imports & Exports

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Zinc Production by Province in 2014

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80% of Chinese Firms Purchasing Overseas Mines Ended up in the Red

<正>Minmetals Resources acquired the world’s largest copper mine under construction for USD5.85 billion.One after another,listed companies Jien Nickle,China Molybdenum and Chihong Zinc and Germanium raised money to get involved in overseas mining projects…SOEs and private enterprises are engaged in a frenzy of overseas mine purchasing.A reporter with Economic     

Copper Processing Profit Dropped Sharply,Copper Consumption Will Face Impact in the Second Half of the Year

正Judging from China’s copper consumption field,the biggest consumption unit is electric power,which accounts for 47%of total consumption;it is followed by light industry sector,including household electrical appliance,machinery,durable goods and hardware etc,which accounts for 22%of total consumption;followed by transportation field,     

Central Geological Prospecting Fund Newly Added 16.47 Million Tonnes of Bauxite in 2013

正In 2013,the Central Geological Prospecting Fund(CGPF)Project newly discovered 15 ore fields,including 3 large above ore fields,and 5medium sized ore fields.The reporter learned from the recently published"Annual Report of Central Geological Prospecting Fund Project(2013)"that,from 2006 to 2013 the CGPF     

Manufacturers of Copper Tube for Central Air Conditioner Use Face Mounting Pressure in the Final Quarter of the Year

正This year,the investment growth rate of real estate industry continued to slow down,sold area of commercial housing also dropped significantly,which brought huge pressure to the domestic air conditioning manufactures.In the first half of the year,by relying on high growth in national financial expenditure,along with investment in public infrastructure     

Xinjiang Ranks No.1 in Production of Primary Aluminum in China

正Kang Yi,Honorary Chairman of China Nonferrous Metals Industry Association,said recently at the Forum on Development of the Non-ferrous Metals Industry in Central and Western China held in Zhengzhou that,as more and more electrolytic aluminum factories in Xinjiang came into operation,the electrolytic aluminum output of Xinjiang had reached2,275,000 tons in the first 7 months this year,     

Shenhuo Coal Industry and Electricity Power Completed800,000 t/a Aluminum Project in Xinjiang

正"Xinjiang project has been completed according to schedule,but total completion and total start of production are two different concepts,after completion it still needs a gradual process of reaching production target."On the morning of November 3,Shenhuo Coal Industry and Electricity Power told investors the above statement on the investor interaction platform.     

Guangdong Metal Transaction Center has Become the Second Largest Precious Metal Transaction Platform Nationwide

正The reporter learned from Guangdong Province Precious Metal Transaction Center that in 2013the Center maintained healthy development momentum,and had become the second largest precious metal transaction platform in China in terms of market size;currently Guangdong is quickening steps of financial innovation for the Center,aiming to build a transaction center with international core competitiveness.     

Seven Rare Earth Projects Involving Close to 3 Billion Yuan Investment Landed In the HighTech Zone

正On May 22,Baotou Rare Earth Industry Cooperation Consultation MeetingProject Agreement-signing Ceremony was held in Ningbo,nearly 40 enterprises from Ningbo,Guangdong,Hunan,and Shanxi participated in project consultation.After multi-lateral communication,agreements were signed for a total of 7 rare earth projects successfully.